NUMERICAL STUDY ON BLAST FLOWFIELDS INDUCED BY SUPERSONIC PROJECTILESDISCHARGED FROM SHOCK-TUBES

In this paper we report on a numerical study of the blast flowfield ge nerated by a supersonic projectile released from the open-end of a sho ck tube into ambient air. The Euler equations, assuming axisymmetric f lows, were solved using a dispersion-controlled scheme implemented wit h moving boundary conditions. Two initial test cases were calculated. One of them is for validation of the numerical method and the other fo r verification of the moving boundary conditions. After good agreement was achieved, four further cases were calculated for examining effect s of various projectile speeds and different release times of the proj ectile after the precursor shock wave was discharged. The present nume rical study confirms that complicated transient phenomena exist in the initial stages shortly after projectile release, and that the blast f lowfield is much more complex than that which can be inferred from muz zle blast studies where combustion products obscure the flow. (C) 1998 American Institute of Physics.